Magnetic head suspension

ABSTRACT

A magnetic head suspension having a thin metallic plate as a substrate which is caused to have a new function besides a function as a spring. The magnetic head suspension plural lines for connecting a magnetic head and a control circuit board to each other are formed over a thin metallic plate having a spring property through an insulating layer, and are integrated with the thin metallic plate A metallic pad made of a same metal layer as the plural lines is formed independently of the lines, an opening is made in a portion of the metallic pad to penetrate the insulating layer and then to reach the thin metallic plate, and an electroconductive region is formed into the opening by metal plating, thereby connecting the metallic pad and the thin metallic plate electrically to each other. Thereby, the desired portions of the suspension can be grounded through this simple structure without adopting a complicated structure wherein additional special lines for grounding are not separately laid besides the lines, which are lines for connecting a magnetic head and a control circuit board to each other.

TECHNICAL FIELD

The present invention belongs to a technical field of a magnetic headsuspension assembly used in a hard disk drive (HDD), and relatesparticularly to a magnetic head suspension with which lines forconnecting a magnetic head and a control circuit board to each other areformed to be integrated.

BACKGROUND ART

In recent years, due to the spread of the Internet and others, theinformation processing amount of personal computers and the processingspeed of information have been required to be increased. Following tothat, it has been requested that the capacity of hard disc drives (HDDs)integrated into personal computers and the speed of informationtransmission are made larger. The type of the component for supporting amagnetic head used in an HDD, which is called a magnetic headsuspension, has also been shifting from a conventional type, to whichsignal lines such as gold wires are connected, to a wiring-integratedtype, i.e., the so-called wireless suspension type, wherein signal linessuch as copper wires are formed directly to a stainless steel spring.

As one out of processes for producing such a wiring-integrated typesuspension, Japanese Patent Application Laid-Open No. 8-180353 disclosesa process of using a laminated plate composed of a layer of aspring-property metal such as stainless steel, an insulating layer, andan electroconductive layer, patterning the spring-property metal layerand the electroconductive layer into a predetermined pattern, and thenremoving the insulating layer partially by plasma etching. This makes itpossible to yield a magnetic head suspension wherein plural lines forconnecting a magnetic head and a control circuit board to each other areformed on a thin metallic plate having the spring property so as to beintegrated with the plate in the state that the insulating layer isinterposed between the plate and the lines.

Patent Document: Japanese Patent Application Laid-Open No. 8-180353DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

As described above, magnetic head suspensions each have a structurewherein plural lines for connecting a magnetic head and a controlcircuit board to each other are formed on a thin metallic plate havingspring properties so as to be integrated with the plate in the statethat an insulating layer is interposed therebetween. For the thinmetallic plate, which constitutes the substrate of the suspension(flexure), a flexible metal, such as SUS, is used to cause the plate tofunction as a spring when the suspension is used. However, the thinmetallic plate, which functions as a spring besides as a base, does notfulfill any especial function other than these functions. Accordingly,if some additional function can be supplied to the thin metallic plate,the resultant magnetic head suspension is convenient. Besides, if thesupply can easily be attained, the magnetic head suspension isespecially convenient.

In light of the situation, the present invention has been made. Anobject thereof is to provide a magnetic head suspension wherein a thinmetallic plate as a substrate is caused to have a new function besides afunction as a spring.

Means for Solving the Problems

The present invention provides a magnetic head suspension (an inventionaccording to claim 1), in which plural lines for connecting a magnetichead and a control circuit board to each other are formed over a thinmetallic plate having a spring property through an insulating layer, andare integrated with the thin metallic plate, characterized in that ametallic pad made of a same metal layer as the plural lines is formedindependently of the lines, an opening is made in a portion of themetallic pad to penetrate the insulating layer and then reach the thinmetallic plate, and an electroconductive region is formed into theopening by metal plating, thereby connecting the metallic pad and thethin metallic plate electrically to each other.

The present invention further provides a magnetic head suspension (aninvention according to claim 2, which is the magnetic head suspensionaccording to claim 1), characterized in that the metallic pad is formedadjacently to a mounting section for a magnetic head slider, and aconnecting section for connecting to the magnetic head slider is formedto the metallic pad.

The present invention also provides a magnetic head suspension (aninvention according to claim 3, which is the magnetic head suspensionaccording to claim 1), characterized in that the metallic pad is formedin a portion of a ground line for restraining interference of signalspassing in the lines.

EFFECT OF THE INVENTION

In the magnetic head suspension which is an invention according to claim1, a metallic pad made of the same metal layer as the plural lines isformed independently of the lines, an opening is made in a portion ofthe metallic pad to penetrate an insulating layer to reach a thinmetallic plate, and an electroconductive region is formed into theopening by metal plating, thereby connecting the metallic pad and thethin metallic plate electrically to each other. Therefore, thesuspension can have a new function that its desired portions can beearthed through its simple structure without adopting a complicatedstructure, wherein additional special lines for earthing are notseparately laid besides the above-mentioned lines, which are lines forconnecting a magnetic head and a control circuit board to each other.The metallic pad (a kind of connecting terminal) is connected to thethin metallic plate at the electroconductive region, which is formed bythe metal plating, thus, in this case, the connection resistance can bemade lower than in a case where such connection is attained by effect ofan electroconductive paste.

The magnetic head suspension which is an invention according to claim 2is the magnetic head suspension according to claim 1 wherein themetallic pad is formed adjacently to a mounting section for a magnetichead slider, and a connecting section for connecting to the magnetichead slider is formed to the metallic pad. Therefore, when theconnecting section is connected to the ground of the magnetic headslider, electric charges collected in the magnetic head slider can bereleased to the thin metallic plate. Thus, an antistatic measure caneasily be taken.

The magnetic head suspension which is an invention according to claim 3is the magnetic head suspension according to claim 1 wherein themetallic pad is formed in a portion of a ground line for restraininginterference of signals passing in the lines. Thus, it is unnecessarythat the ground line is laid along the lines up to the end so as to beconnected to the earth. As a result, the ground line is laid on anecessary region, and through this simple structure, signals can be madestable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating an example of a first embodiment of thepresent invention, and is an enlarged plan view illustrating a tipportion of a magnetic head suspension, on which a magnetic head slideris mounted.

FIG. 2 is an X-X sectional view of FIG. 1.

FIG. 3 is a view illustrating an example of a second embodiment of thepresent invention, and is an enlarged plan view illustrating a middleportion of a magnetic head suspension, through which lines passes.

FIG. 4 is an X-X sectional view of FIG. 3.

FIGS. 5A to 5D are process charts of a first stage of a production of amagnetic head suspension for the present invention.

FIGS. 6A to 6C are process charts of a second stage of the production ofthe magnetic head suspension for the present invention.

FIG. 7A to 7D are process charts of a third stage of the production ofthe magnetic head suspension for the present invention.

DESCRIPTION OF REFERENCE NUMBERS

1: thin metallic plate

2: insulating layer

3: lines

4: platform

5: mounting section

6: metallic pad

6 a: connecting section

7: metallic layer

8: opening

9: electroconductive region

10: ground line

10 a: metallic pad

11: thin metallic plate

12: insulating layer

13: electroconductive layer

14 and 15: resists

16 and 17: resists

18: opening

19: wiring plating

20 and 21: resists

22: electroconductive regions

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in detail on the basis ofillustrated embodiments hereinafter.

First Embodiment

FIG. 1 is a view illustrating an example of a first embodiment of thepresent invention, and is an enlarged plan view illustrating a tipportion of a magnetic head suspension, on which a magnetic head slideris mounted. FIG. 2 is an X-X sectional view of FIG. 1.

The magnetic head suspension has a structure wherein four lines 3, in apattern form, made of Cu, are formed on SUS, which works as a thinmetallic plate 1, having spring properties to be integrated with theplate 1 in the state that a polyimide, which works as an insulatinglayer 2, is interposed therebetween. Gold plating is applied, as wiringplating, onto the individual lines 3 ordinarily over the whole thereof.

The four lines 3 illustrated in FIG. 1 are lines for connecting amagnetic head and a control circuit board to each other. For example,two lines on the right side of the figure, out of the lines 3, are linesfor a writing magnetic head element and the other two lines, on the leftside thereof, are lines for a reading magnetic head element. The twosout of these lines 3 each constitute a pair, and the pair extends fromthe root side of the suspension toward the tip portion, and issubstantially orthogonally curved at a platform 4. Furthermore, the pairis again substantially orthogonally curved toward a mounting section 5for a magnetic head slider. In single-ends of the individual curvedlines 3, the following are formed: connecting sections 3 a, for wiring,connected through solder to four connecting sections, respectively,fitted to the tip side of the magnetic head slider.

In the magnetic head suspension in FIG. 1, a metallic pad 6 is formed inthe platform 4 adjacent to the mounting section 5 for the magnetic headslider, and the metallic pad 6 is equipped with a connecting section 6 awhich passes between the two right lines 3 and the two left lines 3 andattains connection to the ground of the magnetic head slider. Asillustrated in FIG. 2, this metallic pad 6 is made of the same metalliclayer 7 as the lines 3, but is formed independently of the lines 3. Anopening 8 is made in a portion of this metallic pad 6, which is in anisland form, to penetrate the insulating layer 2 and then reach the thinmetallic plate 1. An electroconductive region 9 is formed in the opening8 by metal plating. In this way, the metallic pad 6 and the thinmetallic plate 1 are electrically connected to each other. Examples ofthe metal used in the metal plating for this electroconductive region 9include Ni, Cu, Au and Ag.

In the case of Ni plating, such an electroconductive region based onmetal plating makes it possible to connect the thin metallic plate andthe metallic pad electrically to each other with low resistance valuesof 0.25Ω or less, and 0.20Ω or less when the diameter of the opening is100 μm and 200 μm, respectively, as shown in Table 1. The resistancevalue of each electroconductive region shown in Table 1 is a valueobtained by measuring the electroconductive region and the thin metallicplate near the opening with a four-terminal tester. This resistancevalue includes the contact resistance between it and a measuringterminal on the SUS surface.

TABLE 1 Resistance value (Ω) of electroconductive region based on Niplating Diameter of opening Sample Nos. 100 μm 200 μm 1 0.25 Ω 0.19 Ω 20.23 Ω 0.20 Ω 3 0.21 Ω 0.18 Ω 4 0.23 Ω 0.17 Ω 5 0.19 Ω 0.18 Ω

According to the magnetic head suspension having this structure,electric charges stored in the magnetic head slider can be released tothe side of the thin metallic plate 1 by connecting the connectingsection 6 a of the metallic pad 6 to the ground of the magnetic headslider. The connection at this time is attained by GBB (gold ballbonding) or SBB (solder ball bonding).

Recently, demands for HDDs to be mounted onto various small-sizeddevices, typical examples thereof including portable devices, have beenincreasing, thus, the density of the HDDs has been made high, andfurther the size of magnetic heads has been becoming small. The magneticheads have been more easily affected by electrostatic charging as thesensitivity of the magnetic heads has been made higher. Accordingly, theproperty of a small-sized magnetic head element is changed by electriccharges stored in its slider. At worst, that the risk of breaking theelement is large. Conventionally, the magnetic head slider is earthed byuse of electroconductive paste when the slider is mounted on SUS.However, the adoption of a structure as described above makes theelectric resistance lower than the adoption of electroconductive paste.Additionally, the slider itself can be fixed with an inexpensiveadhesive, therefore, electrical reliability can be surely kept at lowcosts.

It can be earthed to the thin metallic plate at any location thereof.Thus, the present invention has an advantage that the flexibility ofdesign is improved. For example, the metallic pad 6 may be formed at asite adjacent to the rear of the mounting section 5 for the magnetichead slider. In other words, the metallic pad 6 may be formed to causethe connecting section 6 a to face the mounting section 5 on a sideopposite to the side illustrated in FIG. 1. Such an arrangement of themetallic pad 6 makes it possible to fix, without using any adhesivesheet or bonding paste, the magnetic head slider at the same time whenthe connecting section 6 a is connected to the ground.

Second Embodiment

FIG. 3 is a view illustrating an example of a second embodiment of thepresent invention, and is an enlarged plan view illustrating a middleportion of a magnetic head suspension, through which lines passes. FIG.4 is an X-X sectional view of FIG. 3.

This magnetic head suspension has a structure wherein four lines 3, in apattern form, made of Cu are formed on SUS, which works as a thinmetallic plate 1, having spring properties to be integrated with theplate 1 in the state that a polyimide, which works as an insulatinglayer 2, is interposed therebetween. Gold plating is applied, as wiringplating, onto the individual lines 3 ordinarily over the whole thereof.In FIG. 4, the wiring plating is omitted.

The four lines 3 illustrated in FIG. 3, which are other than the center,are lines for connecting a magnetic head and a control circuit board toeach other. For example, two lines on the right side of the figure, outof the lines 3, are lines for a writing magnetic head element and theother two lines, on the left side thereof, are lines for a readingmagnetic head element. In this magnetic head suspension in FIG. 3, aground line 10 for restraining interference of signals passing in thelines 3 is laid between the twos of the lines 3. A metallic pad 10 a isformed in a portion of the line 10. As illustrated in FIG. 4, thismetallic pad 10 a is made of the same metallic layer as the lines 3, butis formed independently of the lines 3. An opening 8 is made in aportion of this metallic pad 10 a, in which a portion of the ground line10 is enlarged, to penetrate the insulating layer 2 and then reach thethin metallic plate 1. An electroconductive region 9 is formed in theopening 8 by metal plating. In this way, the metallic pad 10 a and thethin metallic plate 1 are electrically connected to each other. Examplesof the metal used in the metal plating for this electroconductive region9 include Ni, Cu, Au and Ag, as described above.

According to the magnetic head suspension having this structure,interference between both signals is restrained by laying the groundline 10 between the writing lines 3 and the reading lines 3 laid on theinsulating layer 2. Thus, the signals can be made stable.Conventionally, a ground line 10 is laid along lines 3 up to the rearend of a suspension, and further the line 10 is connected to the earth.However, the setting of the above-mentioned metallic pad 10 makes itpossible to restrain noises easily onto signals passing in the lines 3when the thin metallic plate 1 is connected to the earth common to theplate 1 and the control circuit. Moreover, when the thin metallic plate1 is connected to the earth common to the plate 1 and the controlcircuit, common earthing can be attained through the plate 1 withoutlaying any ground line common to the control circuit board and the plate1. As a result, the arrangement of lines, or the like is easilydesigned. In other words, ground lines are laid only in necessaryregions, about each of the ground lines, the electroconductive region 9based on plating can be formed in the thin metallic plate 1. For thisreason, the following form may be adopted: a form in which ground linesare laid on both side of a line, or a form in which ground lines arelaid in positions apart from each other.

The above has described the two embodiments of the magnetic headsuspension according to the present invention. Processes for producingthem are basically equal to each other. With reference to process chartsof FIGS. 5 to 7, the production process thereof will be describedhereinafter. FIGS. 5 to 7 each illustrate a situation that lines areformed by the right half thereof and a situation that a metallic pad isformed by the left half thereof.

Prepared is a laminate plate illustrated in FIG. 5A, that is, a laminateplate comprising: SUS as a thin metallic plate 11 having springproperties, a polyimide as an insulating layer 12, and Cu as anelectroconductive layer 13. First, the thin metallic plate 11, which isa metallic member, and the electroconductive layer 13 are etched so asto be patterned. Specifically, as illustrated in FIG. 5B, resists suchas dry films are laid on both surfaces of the laminate, respectively.They are each patterned into a predetermined form. Thereafter, asillustrated in FIG. 5C, the workpiece is etched from both surfacesthereof. Next, the resists, which are resists 14 and 15, are peeled off,as illustrated in FIG. 5D.

Subsequently, the insulating layer 12, which is located in the middle,is etched so as to be patterned. Specifically, as illustrated in FIG.6A, resists 16 and 17, such as dry films, are laid to cover thepatterned thin metallic plate 11 and electroconductive layer 13, andthey are each patterned into a predetermined form. Thereafter, asillustrated in FIG. 6B, the electroconductive layer 13 is etched fromboth surfaces thereof. As illustrated in FIG. 6C, the resists 16 and 17are then peeled off. In this way, in the metallic pad, an opening 18 ismade which penetrates the insulating layer 12 to reach the thin metallicplate 11.

Next, a sparger and the like are used to conduct a plating step twotimes, thereby forming wiring plating and electroconductive regions.Specifically, as illustrated in FIG. 7A, a wiring plating 19, such asgold plating, is applied onto the electroconductive layer 13 includingthe metallic pad, and then resists 20 and 21, such as dry films, arelaid on both surfaces thereof, respectively. As illustrated in FIG. 7B,the resist 20 on the wiring side is patterned to exclude the opening 18in the metallic pad. As illustrated in FIG. 7C, metal plating is thenapplied to the workpiece to form an electroconductive region 22. Asillustrated in FIG. 7D, the resists 20 and 21 are peeled off. In thisway, the metallic pad and the thin metallic plate 11 are electricallyconnected to each other through the electroconductive region 22. In thisstep, the wiring plating 19 is applied also to the electroconductivelayer 13 of the metallic pad. However, this is not necessarily required.Finally, a protecting cover layer is optionally laid on the wiringlines.

The above has described the embodiments of the present invention indetail, however, the magnetic head suspension of the present inventionis not limited to the embodiments. The embodiments may be variouslymodified as far as the modifications do not depart from the subjectmatter of the present invention.

1. A magnetic head suspension, in which plural lines for connecting amagnetic head and a control circuit board to each other are formed overa thin metallic plate having a spring property through an insulatinglayer, and are integrated with the thin metallic plate, wherein ametallic pad made of a same metal layer as the plural lines is formedindependently of the lines, an opening is made in a portion of themetallic pad to penetrate the insulating layer and then reach the thinmetallic plate, an electroconductive region is formed into the openingby Ni plating, thereby connecting the metallic pad and the thin metallicplate electrically to each other, and a resistance value of theelectroconductive region for connecting the metallic pad and the thinmetallic plate electrically to each other is from 0.17Ω to 0.25Ω.
 2. Themagnetic head suspension according to claim 1, wherein the metallic padis formed adjacently to a mounting section for a magnetic head slider,and a connecting section for connecting to the magnetic head slider isformed to the metallic pad.
 3. The magnetic head suspension according toclaim 1, wherein the metallic pad is formed in a portion of a groundline for restraining interference of signals passing in the lines. 4.The magnetic head suspension according to claim 2, wherein the metallicpad is formed at a site adjacent to a front of the mounting section forthe magnetic head slider.
 5. The magnetic head suspension according toclaim 2, wherein the metallic pad is formed at a site adjacent to a rearof the mounting section for the magnetic head slider.
 6. The magnetichead suspension according to claim 3, wherein a ground line is providedbetween two writing lines and two reading lines.
 7. The magnetic headsuspension according to claim 1, wherein a diameter of the opening, towhich the Ni plating is applied, is from 100 μm to 200 μm.
 8. A processfor producing a magnetic head suspension, comprising at least followingsteps of: a step of preparing a laminate plate, in which a thin metallicplate and an electroconductive layer are bonded to each other through aninsulating layer, a step of patterning the thin metallic plate and theelectroconductive layer by etching, a step of patterning the insulatinglayer into a predetermined form by etching, thereby making an opening ina metallic pad, a step of covering the thin metallic plate and theelectroconductive layer with an insulating film in their regions otherthan the opening for connecting the thin metallic plate and theelectroconductive layer electrically to each other, and a step of usingthe thin metallic plate as a power-feeding layer to conduct metalplating, thereby connecting the thin metallic plate and the metallic padof the electroconductive layer electrically to each other.
 9. Theprocess for producing a magnetic head suspension according to claim 8,wherein the metallic pad is formed adjacently to a mounting section fora magnetic head slider, and a connecting section for connecting to themagnetic head slider is formed to the metallic pad.
 10. The process forproducing a magnetic head suspension according to claim 8, wherein themetallic pad is formed in a portion of a ground line for restraininginterference of signals passing in the lines.
 11. The process forproducing a magnetic head suspension according to claim 9, wherein themetallic pad is formed at a site adjacent to a front of the mountingsection for the magnetic head slider.
 12. The process for producing amagnetic head suspension according to claim 9, wherein the metallic padis formed at a site adjacent to a rear of the mounting section for themagnetic head slider.
 13. The process for producing a magnetic headsuspension according to claim 10, wherein the ground line is providedbetween two writing lines and two reading lines.
 14. The process forproducing a magnetic head suspension according to claim 8, wherein themetal plating of an electroconductive region for connecting the metallicpad and the thin metallic plate electrically to each other is Niplating.
 15. The process for producing a magnetic head suspensionaccording to claim 14, wherein a resistance value of theelectroconductive region for connecting the metallic pad and the thinmetallic plate electrically to each other is from 0.17Ω to 0.25Ω. 16.The process for producing a magnetic head suspension according to claim8, wherein a diameter of the opening, to which the metal plating isapplied, is from 100 μm to 200 μm.